Accepting bids to advertise to users performing a specific activity

ABSTRACT

A facility for Performing on-line advertising at a subject web site relative to a selected user activity is described. The facility receives a plurality of bids. Each bid is submitted on behalf of an advertiser, and specifies an advertising rate that the advertiser will pay to display an advertising messages to users performing the selected activity with respect to the subject web site. When a request for any web page of the subject web site containing advertising space is received from a user that has previously performed the selected activity, irrespective of the identity of the requested web page, the facility both (1) identifies the received bid specifying the largest advertising rate, and (2) causes an advertising message to be displayed in the advertising space of the requested web page for the advertiser on whose behalf the identified bid was submitted.

CROSS REFERENCE(S) TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/830,874, filed Apr. 23, 2004, now abandoned which is a continuationof U.S. patent application Ser. No. 10/653,703, filed Sep. 2, 2003, bothof which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention is directed to techniques for targeted on-lineadvertising.

BACKGROUND

A web site is a group of related web pages that are available forretrieval via the Internet or another computer network. Parties thatmaintain web sites are sometimes called “publishers.” Some publisherssell to advertisers opportunities to include advertising messages ontheir web sites. For example, the publisher of a news web site may sellto an advertiser selling residential inspection services an opportunityto include advertisements on the publishers web site.

In particular, publishers often sell opportunities to includeadvertising on particular pages of publishers' web sites having specialsignificance. For example, because residential inspection services maybe valuable to people who are in the market for a house, the publisherof the news web site may sell to the residential inspection servicesadvertiser an opportunity to include advertisements on pages of thepublishers web site containing articles about real estate sales. Asanother example, the publisher may sell to the residential inspectionservices advertiser an opportunity to include advertisements on searchresult pages produced from user queries containing the search term “homesales.”

Because some pages on a web site have more advertising significance thanothers, advertiser demand to include advertising messages on aparticular web site may vary widely from one page of the web site toanother. This is disadvantageous in several respects. First, moresignificant pages are oversubscribed, in that some advertisers that wantto advertise there are unable to do so. Advertisers may have to foregoreceiving advertising revenue from advertisers that would haveadvertised on these pages if they were not oversubscribed. Second, lesssignificant pages are undersubscribed, in that there are not enoughadvertisers that want to advertise on these pages to purchase all of theavailable advertising capacity there. In the case of these pages, thepublisher either must sometimes serve the page without any advertising,generating no incremental advertising revenue, or must acceptlocation-insensitive messages at a very low price.

Another disadvantage of this approach is that, while the fact that aparticular user has requested retrieval of a page relating to aparticular subject may in some cases accurately predict that the userwill be interested in advertising related to a similar subject, the useroften has no such interest. Accordingly, presenting advertising in thismanner often has a fairly low level of effectiveness.

In view of the above-discussed disadvantage of conventional approachesto web advertising, a new approach that overcame these disadvantageswould have significant utility.

SUMMARY

A software facility for presenting targeted advertising messages in alocation-agnostic manner is described. In some embodiments, the facilitydetermines that a number of users are part of a distinct audience, suchas an audience sharing a common interest, based upon activitiesperformed by these users while visiting a publisher's web site, alsocalled the “subject web site.” The facility specifies that the users inthis audience will receive advertising messages relating to the natureof the audience, such as the audience's common interest, on any pagesthat these users subsequently visit on the publisher's web site.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high-level block diagram showing a typical environment inwhich the facility operates.

FIG. 2 is a flow diagram showing steps typically performed by thefacility in order to add a new activity to those on which advertiserscan bid.

FIG. 3 is a display diagram showing a sample web page that advertisersmay use in order to bid on an activity performed by users on the subjectweb site.

FIG. 4 is a data structure diagram showing a sample bid queue for aparticular activity.

FIG. 5 is a flow diagram showing steps typically performed by thefacility in order to select an advertising message to include in a webpage that the user has requested from the subject web site.

DETAILED DESCRIPTION

A software facility for presenting targeted advertising messages in alocation-agnostic manner (“the facility”) is described. In someembodiments, the facility determines that a number of users are part ofa distinct audience, such as an audience sharing a common interest,based upon activities performed by these users while visiting apublisher's web site, also called the “subject web site.” The facilityspecifies that the users in this audience will receive advertisingmessages relating to the nature of the audience, such as the audience'scommon interest, on any pages that these users subsequently visit on thepublisher's web site.

The activities performed by users that qualify them as members of aparticular audience can be of a number of different types. A firstactivity type is action-based activities, each of which involvesperforming a set of actions, such as interacting with a loan calculatormade available by the publisher on its web site to obtain a loancalculator result. A second activity type is reading-based activities,each of which involves reading at least a minimum number of web pagescontaining a particular set of key words or matching a particular query.A third activity type is category-based activities, which involvevisiting one or more specific categories of the publisher's web sitewith at least a minimum frequency.

In some embodiments, advertisers bid on opportunities to advertise toparticular audiences. These bids are accepted from advertisers either bythe publisher directly, or through an intermediary, such as anindependent operator of the facility. When an advertiser submits a bid,the advertiser specifies such aspects as the identity of the audience; arate per thousand impressions that the advertiser will pay to displayadvertising messages to members of the audience; a maximum amount ofmoney that the advertiser is willing to spend; a date on which theadvertising will conclude, irrespective of whether the budget has beenexhausted; and an advertising message to be displayed. Where thisauction system is used to sell advertising, when a user requests a pageof the publishers web site, the facility identifies any audiences forwhich the user has qualified based upon the users activities on thepublishers web site. The facility then selects bids for particular usersbased—at least in part—upon the advertising rates specified for thebids, and incorporates the advertising message specified by the selectedbids into the requested pages. In some embodiments, the facilityprovides mechanisms other than auctions that enable advertisers topurchase opportunities to advertise to particular audiences. Forexample, in some embodiments, the facility accepts requests to advertiseto particular audiences based upon a fixed price, or based upon a priceautomatically determined with reference to a variety of pricing factors.

In some embodiments, the facility auctions or otherwise sellsopportunities to advertise to members of a particular audience duringspecific sessions, i.e., individual visits to the subject web site, alsocalled “sessions.” For example, in some such embodiments, the facilityaccepts bids for advertising opportunities that, in addition to audienceidentity and advertising rate, also specify a maximum number ofadvertising impressions to present per session. In these embodiments,the facility typically selects, at the beginning of each new session, abid to use in advertising to the user visiting the subject web siteduring that new session. In some of these embodiments, the selected bidis the only bid for its audience that will be used to advertise to theuser during the new session. Such bid selection is typically performedbased upon expected values calculated for each of the bids, which maytake into account each bid's advertising rate and maximum number ofimpressions per session, as well as an expected number of impressionopportunities per session. This expected number of advertisingopportunities may be determined manually by a human user, or may becalculated based upon data for all visitors to the subject web site,users in the same audience or audiences as the presently-visiting user,or the presently-visiting user as an individual. By selling sessionadvertising opportunities as described above, embodiments of thefacility are able to re-establish a sense of scarcity for advertisingopportunities that may otherwise be lost when the facility dissociatesadvertising opportunities from specific web pages on the subject website.

By presenting advertising messages in manners such as those describedabove, embodiments of the facility enable a publisher to obtain a numberof valuable benefits. As one example, the use of rich activities toqualify users for audiences enables the publisher to sellbetter-targeted advertising at a higher average price. Further, becauseadvertising messages can be presented to users of an audience on anypage of the publisher's web site after these users have performed theactivity that qualifies them for the audience, the publisher enables anadvertiser to “follow” users in the audience, presenting a larger bodyof advertising messages to users in the audience as they navigate frompage to page of the publisher's web site, both facilitating moreeffective advertising campaigns and making it likely that advertiserswill purchase greater advertising volume from the publisher. Also, thefact that advertising messages can be presented to users of an audienceon any page of the publisher's web site after these users have performedthe activity that qualifies them for the audience improves the value of,and therefore the level of revenue produced by, pages on the web sitethat have less inherent advertising significance or less traffic.Additionally, the use of auctions to sell the advertising space adds thebenefits of simplifying the purchase of advertising space, making suchpurchase accessible to a larger group of advertiser and maximizing therevenue obtained from each advertising opportunity.

FIG. 1 is a high-level block diagram showing a typical environment inwhich the facility operates. The block diagram shows several clientcomputer systems, such as client computer systems 110, 120, and 130.Each of the client computer systems has a web client computer programthat a user of the client computer system can use to browse the WorldWide Web, such as web clients 111, 121, and 131. Such web clientstypically allow web servers within particular domains to store data in aform called a cookie on a client computer system as part of the processof responding to a request from the web client on that client computersystem. Such cookies may be used to store information uniquelyidentifying the client computer system and/or its user, among otherinformation. The web client forwards the information stored in a cookiewith each future request it makes to the domain that created the cookie.The client computer systems are connected via the Internet 140 to aserver computer system 150 hosting the facility. Those skilled in theart will recognize that client computer systems could be connected tothe server computer system by networks other than the Internet, however.

The server computer system 150 contains a memory 160. The memory 160preferably contains the facility 161, comprising one or more programs162, as well as data 163. The memory preferably further contains a webserver computer program 165 for delivering web pages in response torequests from web clients, as well as one or more logs 164 containinginformation about requests received and serviced by the web server.While items 161-165 are preferably stored in memory while being used,those skilled in the art will appreciate that these items, or portionsof them, maybe be transferred between memory and a persistent storagedevice 172 for purposes of memory management and data integrity. Theserver computer system further contains one or more central processingunits (CPU) 171 for executing programs, such as programs 161-164, and acomputer-readable medium drive 173 for reading information or installingprograms such as the facility from computer-readable media, such as afloppy disk, a CD-ROM, or a DVD.

While various embodiments of the facility are described in terms in theenvironment described above, those skilled in the art will appreciatethat the facility may be implemented in a variety of other environmentsincluding a single, monolithic computer system, as well as various othercombinations of computer systems or similar devices connected in variousways. In particular, the facility may interact with users via a widerange of portable and/or wireless user interface devices, such ascellular telephones, pagers, personal digital assistants, etc.

FIG. 2 is a flow diagram showing steps typically performed by thefacility in order to add a new activity to those on which advertiserscan bid. Embodiments of the facility can perform these steps for each ofa number of different activities. In step 201, the facility creates adefinition of the new activity that may be automatically applied toidentify users who have performed the activity. In some embodiments, theactivity definitions created in step 201 are consistent with thosedescribed in U.S. Patent Application Nos. 60/479,353 and 60/479,609,both filed on Jun. 17, 2003, each of which is hereby incorporated byreference in its entirety.

The facility typically creates definitions of action-based activitiesbased upon the input of a user, such as an on-line marketing specialist.The user typically selects one or more types of actions that must beperformed as part of the activity, a number of times each of the actionsmust be performed, and an amount of time in which the required number ofeach of the actions must be performed.

The facility enables advertisers to manually define reading-basedactivities by specifying a group of key words that may be found on pagesof the subject web site, or by specifying search queries built usinglogical operators that may be used to search the pages of the subjectweb site or an index thereon, such as the following:

-   -   “Ford” AND NOT (“Gerald” OR “President”)    -   “Ford” NEAR “SUV”    -   “Ford” AND NOT “Chrysler”        A user performs such an activity by requesting at least a        minimum number of pages of the subject web site containing the        group of key words or satisfying the query within a particular        period of time, or by requesting pages of the subject web site        whose scores for satisfying the query sum to at least a minimum        total score.

The facility can also automatically define reading-based activities byapplying clustering algorithms and/or frequent set algorithms to dataobtained from web logs identifying each request made for a particularpage of the subject web site by a particular user at a particular time,in order to identify groups of pages of the subject web site where mostor all of the pages of each group have been visited by each of asignificant number of individual users. For each of these groups ofpages, the facility compares the text appearing on each of the pages ofthe group to identify words or groups of words that occur on most or allof the pages of the group. In some embodiments, information retrievaltechniques are applied to select those words or groups of words thatboth are contained by most or all of the pages of the group, and arecontained by few or none of the pages of the subject web site that arenot in the group. For some or all of these groups of pages, the facilitycreates a reading-based activity definition that requires users to visita certain number of pages of the subject web site containing the wordsor sequence of words selected for the group, at least a minimum numberof times in a specified period of time. The facility may permit a user,such as an on-line marketing specialist, to select groups that will bethe basis for a reading-based activity, and specify the necessaryparameters for each reading-based activity.

To create a definition for category-based activities, the facilityreceives input from a user, such as an on-line marketing specialist,identifying one or more categories of the subject web site, andspecifying the number of pages in those categories that a user mustvisit to perform their activity, and the amount of time in which theuser must visit them.

After step 201, the facility continues in both steps 202 and 203 inparallel. Those skilled in the art will appreciate that, while steps 202and 203 are independent, enabling them to be performed in parallel, theyneed not be performed in a truly parallel manner, in the computerscience sense. In step 202, the facility accepts a bid for the activity.FIG. 3, discussed below, shows details of one approach to accepting bidsfor the activity. After step 202, the facility continues in step 202 toaccept the next bid for this activity.

In step 203, the facility populates a group of users performing theactivity defined in step 201. This group is also referred to as an“audience,” a “segment,” or a “population.” Such population is typicallyperformed by applying a definition created in step 201 to a body of datareflecting the actions of all users to interact with the subject website. For example, a facility may use the techniques described in thepatent applications referenced above to periodically analyze thecontents of a web log and apply one or more activity definitions topopulate groups performing the corresponding activities. In someembodiments, these web log contents are extracted in a manner describedin U.S. patent application Ser. No. 09/613,403 filed on Jul. 11, 2000,which is hereby incorporated by reference in its entirety. These weblogs may be web logs produced by the operator of the subject web site(also called “the publisher”), or may be a web log generated by a thirdparty, such as the operator of the facility, who has been permitted toincorporate inclusion links specifying a URL in their domain into eachof the pages of the subject web site, or has been permitted to monitorthe interactions of specific users with the subject web site in someother manner. In some cases, rather than periodically processing weblogs or other accumulated information about user interactions with thesubject web site, the facility may intercept every user interaction withthe subject web site in real-time, and reevaluate whether the usershould be added to or removed from any of the groups at that point basedupon the present interaction. As part of step 203, the facility storesindications of which group each user is a member of in a manner andlocation conducive to later determining which groups a particular useris a member of when an advertising request is received for that user.These indications may be stored on the computer system on which thefacility operates, on the computer system of a third-party ad servingservice, or in cookies on each user's client computer system, amongother locations. After step 203, the facility continues in step 203 toagain populate a group performing the defined activity.

FIG. 3 is a display diagram showing a sample web page that advertisersmay use in order to bid on an activity performed by users on the subjectweb site. The web page 300 includes a set of selection user interfaceelements for selecting a particular audience, the members of which eachhave performed a particular activity with respect to the subject website, here radio buttons 301-303. The user may select one of these radiobuttons in order to display additional information about the selectedaudience, and in order to submit a bid to advertise to the selectedaudience. Here, radio button 301 has been selected, thereby selecting anActive Home Buyers audience. Accordingly, the page contains additionalinformation 320 about this audience, indicating how the activity towhich the audience corresponds is defined, and the current size of theaudience. This information may further contain additional aspects of theaudience that may assist potential bidders in determining howappropriate this audience is for use in a particular advertisingcampaign under consideration.

The web page further includes user interface elements 330 for creatingand submitting a bid to advertise to the selected audience. Theseelements include: a bid amount field 331, into which a bidder may enteran amount of money they wish to bid per thousand impressions (that is,presentations) of the advertising message they wish to present; a budgetfield 332, into which the bidder may enter a maximum amount of moneythey wish to commit to the bid—after this budget is reached, the bidwill be completed, and no fuller advertising messages will be presentedin accordance with the bid; an expiration date field 333, into which thebidder may enter a date upon which the bid will expire, and after whichno advertising messages will be presented in accordance with the bid; asource of payment field 334, into which the bidder may enter informationenabling the operator the facility to charge the bidder for advertisingperformed in accordance with the bid, such as a credit card number andexpiration date, or a number identifying a billing account that theoperator of the facility has established for the bidder; and a field 335into which a bidder may enter information specifying a particularadvertising message, such as a URL from which the advertising messagecan be retrieved; and a submit bid button 336 that the bidder may selectafter completing bidding fields 331-335 in order to subject a bid forthe currently-selected audience.

Those skilled in the art will appreciate that the facility may solicitand receive bids in a variety of other ways, including exchanging emailmessages or XML documents; interacting via a specialized biddingprotocol; or interacting via voice telephone call, using eitherautomatic touch tone or voice response systems or transcription by ahuman agent, among other approaches. After a bid is received, a noderepresenting the bid is added to a queue data structure corresponding tothe particular audience to which the bid was directed. These bid queuedata structures are used by the facility to select advertising messagesto be presented to audience members.

FIG. 4 is a data structure diagram showing a sample bid queue for aparticular activity. While those skilled in the art will recognize thatqueue data structures may be arranged in the variety of differentmanners, the queue data structure shown in FIG. 4 is arranged as alinked list. In the linked list, a special head node 410 points to thetop bid node in the list, node 420. This bid node has the highest bidamount of any of the bid nodes in the list: $750. Bid node 420 is linkedto bid node 430, which has the second highest bid amount in the list:$560. Bid node 430 is linked to bid node 440, which has the next-lowestbid amount in the queue: $215. Bid node 440 is linked to a special tailnode 450 denoting the end of the queue. When a new bid is received, thefacility typically inserts a bid node representing the bid into thequeue for the audience to which the bid pertains at the point at whichthe queue continues to be sorted by bid amount. For example, bid node440 corresponding to the bid submission shown in FIG. 3 is added at thebottom of the queue, since its bid amount is lower than the bid amountsof the previously-submitted bids. In some embodiments, where a new bidis received that has the same bid amount as a previously-received bidhaving a bid node in the same queue, the bid node for the new bid isadded to the bid queue below the existing bid node having the same bidamount.

Each bid node typically contains information used to service the bidthat it represents. As an example, bid node 420 contains the followinginformation: in a bid amount field 421, the dollar amount of the bid perthousand impressions, here $750; in an ad field 422, information thatcan be used to retrieve the advertising message that is the subject ofthe bid, here a URL; in a maximum impressions field 423, the maximumnumber of times the advertising message is to be presented in accordancewith this bid, here 4,000 times; in an impressions served field 424, thenumber of times the advertising message has already been presented inaccordance with this bid, here 1125; in an impressions charged field425, the number of served impressions for which the bidder has alreadybeen charged, here 750; in a payment source field 426, informationusable to charge the bidder for served impressions, here a credit cardnumber and expiration date; and, in an expiration date field 427, theday on which the bid expires, and after which no impressions are to beserved in accordance with the bid. The facility's use of bid queues isdiscussed in detail below in conjunction with FIG. 5.

FIG. 5 is a flow diagram showing steps typically performed by thefacility in order to select an advertising message to include in a webpage that the user has requested from the subject web site. In step 501,the facility receives an advertising request for an identified user. Thereceived advertising request typically corresponds to that users requestfor a page of the subject web site. In some embodiments, the facilityreceives this request by virtue of an inclusion link to the domain ofthe operator of the facility added by the operator of the subject website to the page of the web site requested by the user. In steps502-505, the facility loops through each audience of which the user is amember. (For a user that is not a member of any defined audience, or auser that is only a member of audiences for which there are no activebids, the facility typically displays a default advertising message notassociated with the bid for a particular audience (not shown), and omitsthe remaining steps shown.) In step 503, if the bid at the top of aqueue for the current audience is expired—that is, its expiration datehas passed—then the facility continues in step 504, else the facilitycontinues in step 505. In step 504, the facility removes the top bidfrom the current queue, and uses the payment source information tocharge the bidder for any impressions that have been served but not yetcharged, as reflected by the impressions served and impressions chargedfield. After step 504, the facility continues with step 503 to examinethe new top bid node in the current queue. In step 505, if any otheraudiences of which the user is a member remain to be processed, then thefacility continues in step 502 to process the next audience, else thefacility continues in step 506.

In step 506, a facility selects the audience to which the user belongswhose top bid has the highest bid amount. In step 507, the facilityserves the advertising message identified in the add field of the topbid node in the queue for the selected audience. In embodiments in whichthe advertising request received in step 501 was a request in accordancewith an inclusion link on the served page of the subject web site,performing step 507 typically involves sending a redirection response tothe client computer system that redirects the web client on the clientcomputer system to retrieve this advertising message using the retrievalinformation stored in the add field of the bid node. In someembodiments, however, some or all of the advertising messages are storedon the computer system on which the facility executes, in which case thefacility merely returns a copy of the advertising message to the clientcomputer system directly.

In step 508, the facility increments the value in the impressions servedfield of the bid node. In step 509, if the value in the impressionsserved field of the bid node is at least as large as the value in themaximum impressions field of the bid node, then the facility continuesinstep 510, else the facility continues in step 501 to process the nextadvertising request. In step 510, the facility removes the top bid fromthis bid queue, and charges the bidder for any impressions served andnot charged as discussed above in conjunction with step 504. After step510, the facility continues in step 501. In some embodiments, thefacility periodically traverses each of the bid queues, charging thebidder associated with each bid node for impressions served and not yetcharged that are reflected by that bid node, as described above inconjunction with step 504.

In some embodiments, alternative approaches are used to select theadvertising message presented to a particular audience member, such asapproaches that provide greater diversity of advertising messages andadvertisers to individual users. In one such approach, a bid is selectedrandomly from the bid queues corresponding to audiences of which therequesting user is a member, weighting each bid for selection based uponits bid amount. In another such approach, each user “traverses” the bidsin the bid queue, first receiving the advertising message specified bythe top bid in the bid queue, then receiving the advertising messagespecified by the second bid in the bid queue and so on.

Additional embodiments of the facility employ various other approachesfor selecting a bid, or for selecting an advertising message sold usinga mechanism other than an auction. For example, in some embodiments, thefacility accepts requests to advertise to particular audiences basedupon a fixed price, or based upon a price automatically determined withreference to a variety of pricing factors.

In some embodiments, the facility auctions or otherwise sellsadvertising opportunities corresponding to particular browsing sessionsperformed at the subject web site by members of a particular audience.In these embodiments, each time a user begins a new visit to the subjectweb site, the facility chooses an advertiser to sponsor that visit, by(a) identifying the audiences of which the user is a member; (b)identifying all of the bids specifying any of these audiences; (c)determining for each identified bid an expected value representing theanticipated level of advertising revenue that would be produced of thebidder submitting the bid was selected as the sponsor of this visit; (d)selecting the bid having the highest expected value; and (e) during thevisit, presenting advertising messages for the sponsor of the visit,without presenting any advertising messages for the submitters of otherbids specifying the same audience. In some such embodiments, each bidmay specify a maximum number of impressions to present to a user duringa session sponsored by the bid. Once this maximum number of impressionsper session is reached, the facility selects advertising messages notdirected to members of the same audience as the sponsoring bid, such asby presenting advertising messages in accordance with a bid specifying adifferent audience of which the user is a member, or by displayingadvertising messages not associated with any audience-based advertisingbid. In some cases, a bid may further specify a maximum number ofimpressions to be presented to a particular user across all of theirvisits to the subject web site. In some embodiments, the expected valueof a bid is determined by multiplying its per impression or per 1000impression advertising rate by the smaller of the maximum number ofimpressions per session specified by the bid and an expected number ofimpression opportunities. The expected number of impressionopportunities may be determined in a variety of ways, includingdetermining the historical average of number of advertising impressionopportunities per session of the visiting user, or of a variety ofdifferent groups including the visiting user, such as users that aremembers of one or more audiences of which the visiting user is a member,or all users visiting the subject web site.

It will be appreciated by those skilled in the art that theabove-described facility may be straightforwardly adapted or extended invarious ways. For example, the facility may be operated by a singleorganization, or aspects of its functionality may be distributed acrossmultiple organizations. In particular, various functionality may bemoved between the operator of the facility, one or more publishersoperating one or more subject web sites, and advertisers who are biddingto advertise on the subject web sites. The operator of the facility mayuse various approaches to directly charging bidders for advertisingmessages presented in accordance with the bidding process, or may chargethese bidders indirectly through one or more intermediaries. Variousdata structures having variety of forms may be used to support theoperation of the facility, as may be various types of computer code,arranged in various modules in various ways. The facility may be used toauction or otherwise sell the opportunity to present virtually any typeof advertising message to audiences defined in various ways based uponvarious kinds of activities. While the foregoing description makesreference to certain preferred embodiments, the scope of the inventionis defined solely by the claims that follow and the elements recitedtherein.

1. A method in a computing system for providing online advertisingplacements, comprising: receiving a plurality of advertising bids, eachadvertising bid specifying a distinguished action available forperformance by advertising prospects interacting with a subject website, an advertising message that is to be presented to advertisingprospects performing the specified action, a price per impressionoffered to present the specified advertising message to advertisingprospects performing the specified action and a maximum number ofimpressions of the specified advertising message to be presented to thesame advertising prospect during a single visit to the subject web site;storing the received advertising bids; receiving an indication that anew visit to the subject web site by a distinguished advertisingprospect that has performed the distinguished action has taken place;determining for each stored advertising bid an expected value obtainedby multiplying the price per impression specified by the advertising bidby the smaller of the maximum number of impressions per sessionspecified by the advertising bid and an expected number of advertisingopportunities per visit to the subject web site, wherein the storedadvertising bid for which the highest expected value is obtained isselected, and wherein the expected number of advertising opportunitiesper visit to the subject web site is a measured average number ofadvertising opportunities per visit to the subject web site by alladvertising prospects who have performed the specified action; selectingone of the stored advertising bids based upon a comparison of the priceper impression and maximum number of impressions specified by each ofthe stored advertising bids; and displaying the advertising messagespecified by the selected advertising bid, selected based on the highestexpected value in accordance with the determining step, to thedistinguished advertising prospect during the new visit to the subjectwebsite.
 2. The method of claim 1 wherein the maximum number ofimpressions specified by the selected advertising bid of the advertisingmessage specified by the selected advertising bid are presented to thedistinguished advertising prospect during the new visit to the subjectweb site.
 3. The method of claim 2, further comprising, during the newvisit to the subject web site, after the maximum number of impressionsspecified by the selected advertising bid of the advertising messagespecified by the selected advertising bid have been presented to thedistinguished advertising prospect, presenting to the distinguishedadvertising prospect an advertising message not specified by any of thestored advertising bid specifying the distinguished action.
 4. Acomputer-readable medium containing computer codes, when executed by aprocessor, perform the steps of: receiving a plurality of advertisingbids, each advertising bid specifying one of a plurality of actionsavailable for performance by advertising prospects interacting with asubject web site, an advertising message that is to be presented toadvertising prospects performing the specified action, a price perimpression offered to present the specified advertising message toadvertising prospects performing the specified action and a maximumnumber of impressions of the specified advertising message to bepresented to the same advertising prospect during a single visit to thesubject web site; receiving an indication that a new visit to thesubject web site by a distinguished advertising prospect that hasperformed a distinguished action has taken place specified by at leastone of the received advertising bids; determining for each storedadvertising bid an expected value obtained by multiplying the price perimpression specified by the advertising bid by the smaller of themaximum number of impressions per session specified by the advertisingbid and an expected number of advertising opportunities per visit to thesubject web site, wherein the stored advertising bid for which thehighest expected value is obtained is selected, and wherein the expectednumber of advertising opportunities per visit to the subject web site isa measured average number of advertising opportunities per visit to thesubject web site by all advertising prospects who have performed thespecified action; selecting one of the stored advertising bids basedupon a comparison of the price per impression and maximum number ofimpressions specified by each of the stored advertising bids; anddisplaying the advertising message specified by the selected advertisingbid, selected based on the highest expected value in accordance with thedetermining step, to the distinguished advertising prospect during thenew visit to the subject website.